This invention relates to a process for metal plating of plastics and more particularly to plated plastics where the metal platings are composed of main group metals such as Ge, Sn and As. More specifically, the invention relates to the formation of metal platings from certain salts of the main group metals where the main group metal to be deposited is in the negative oxidation state and is oxidized in the process.
Metallized plastics have been found useful in the electrical, automotive and other industries for their electrical, reflective, and decorative properties. Previously, electroless deposition processes have been developed to chemically deposit a metal on a polymeric substrate by a reduction of the metal from a solution of the metal salt. In these previous processes, the polymeric substrate is first sensitized by treatment with certain other metal salts to cause the desired reduction and deposition of metal. While these electroless techniques are useful, they have not generally been applied to the deposition of many of the main group metals.
One technique for chemically depositing main group metals has involved the decomposition of metal hydrides by exposure to hot substrates to form the metal platings. In some instances, the process has been difficult to control and explosive conditions have been encountered. Accordingly, one object of the invention is a chemical process for plating main group metals on a polymeric substrate. A second object is a process for plating main group metals under mild conditions of temperature and pressure. An additional object is a process for plating a polymeric substrate which does not require an initial sensitizing step. Another object is a process for plating a polymeric substrate which provides metal platings having a varied thickness.